Aggregated and Virtualized Solid State Drives Accessed via Multiple Logical Address Spaces

ABSTRACT

A solid state drive having a drive aggregator and multiple component solid state drives. The drive aggregator associates the host interfaces with different logical address spaces, interprets commands received from the host interfaces in the different logical address spaces, and implements the commands using the plurality of component solid state drives. Some of the host interfaces can be configured to share a common logical address space. Some of the logical address spaces can be configured to have an overlapping region that are hosted on the same set of memory units such that the memory units can be addressed in any of the logical address spaces having the overlapping region.

FIELD OF THE TECHNOLOGY

At least some embodiments disclosed herein relate to memory systems ingeneral, and more particularly, but not limited to aggregation andvirtualization of solid state drives that can be accessed using separatelogical address spaces.

BACKGROUND

A memory sub-system can be a storage system, such as a solid-state drive(SSD), or a hard disk drive (HDD). A memory sub-system can be a memorymodule, such as a dual in-line memory module (DIMM), a small outlineDIMM (SO-DIMM), or a non-volatile dual in-line memory module (NVDIMM). Amemory sub-system can include one or more memory components that storedata. The memory components can be, for example, non-volatile memorycomponents and volatile memory components. Examples of memory componentsinclude memory integrated circuits. Some memory integrated circuits arevolatile and require power to maintain stored data. Some memoryintegrated circuits are non-volatile and can retain stored data evenwhen not powered. Examples of non-volatile memory include flash memory,Read-Only Memory (ROM), Programmable Read-Only Memory (PROM), ErasableProgrammable Read-Only Memory (EPROM) and Electronically ErasableProgrammable Read-Only Memory (EEPROM) memory, etc. Examples of volatilememory include Dynamic Random-Access Memory (DRAM) and StaticRandom-Access Memory (SRAM). In general, a host system can utilize amemory sub-system to store data at the memory components and to retrievedata from the memory components.

For example, a computer can include a host system and one or more memorysub-systems attached to the host system. The host system can have acentral processing unit (CPU) in communication with the one or morememory sub-systems to store and/or retrieve data and instructions.Instructions for a computer can include operating systems, devicedrivers, and application programs. An operating system manages resourcesin the computer and provides common services for application programs,such as memory allocation and time sharing of the resources. A devicedriver operates or controls a specific type of devices in the computer;and the operating system uses the device driver to offer resourcesand/or services provided by the type of devices. A central processingunit (CPU) of a computer system can run an operating system and devicedrivers to provide the services and/or resources to applicationprograms. The central processing unit (CPU) can run an applicationprogram that uses the services and/or resources. For example, anapplication program implementing a type of applications of computersystems can instruct the central processing unit (CPU) to store data inthe memory components of a memory sub-system and retrieve data from thememory components.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments are illustrated by way of example and not limitation inthe figures of the accompanying drawings in which like referencesindicate similar elements.

FIG. 1 illustrates an example computing system having a memorysub-system in accordance with some embodiments of the presentdisclosure.

FIG. 2 shows a host system connected to a virtualized single solid statedrive having multiple component solid state drives.

FIG. 3 shows a drive aggregator according to one embodiment.

FIG. 4 shows a method implemented in a drive aggregator according to oneembodiment.

FIG. 5 shows a method of distributing commands received in a virtualizedsolid state drive to solid state drives.

FIG. 6 shows multiple host systems connected to a virtualized singlesolid state drive having multiple component solid state drives.

FIG. 7 shows a drive aggregator having multiple host interfacesaccording to one embodiment.

FIG. 8 shows a host system connected to a virtualized single solid statedrive via multiple parallel and/or redundant connections.

FIG. 9 shows a method of processing commands received in a virtualizedsolid state drive via multiple host interfaces.

FIG. 10 illustrates a virtualized single solid state drive configured tobe accessed via separate logical address spaces according to oneembodiment.

FIG. 11 illustrates a drive aggregator configured to facilitate accessto memory/storage resources in a virtualized single solid state driveusing separate logical address spaces.

FIGS. 12-14 illustrate examples of address maps.

FIG. 15 shows a method of accessing memory/storage resources in avirtualized single solid state drive using separate logical addressspaces.

DETAILED DESCRIPTION

At least some aspects of the present disclosure are directed totechniques to aggregate multiple memory sub-systems as a combined memorysub-system that functions as a single memory sub-system to a hostsystem. In some embodiments, the single memory sub-system is configuredwith multiple host interfaces to service multiple host systems, orservice a host system via multiple parallel and/or redundantconnections.

Currently, a solid state drive (SSD) can be provided in a singleintegrated circuit package. For example, the solid state drive (SSD) canbe packaged with a ball grid array (BGA) form factor. The BGA SSD has acontroller embedded in the integrated circuit package to processcommands from a host system, control operations to access data in mediaunits or memory components embedded in the BGA SSD, and generateresponses to the commands from the host system. However, the singleintegrated circuit package and/or the BGA form factor can limit thestorage capacity of the BGA SSD.

At least some aspects of the present disclosure address the above andother deficiencies through a drive aggregator that is configured toaggregate and virtualize multiple SSDs as a single SSD for the hostsystem. Thus, multiple BGA SSDs can be used to construct one highcapacity SSD for the host system. The combined SSD can have a storagecapacity that is not limited by the single integrated circuit packageand/or the BGA form factor.

In general, the drive aggregator can be used to aggregate and virtualizemultiple memory sub-systems for a host system. One example of a memorysub-system is a storage device that is connected to the centralprocessing unit (CPU) via a peripheral interconnect (e.g., aninput/output bus, a storage area network). Examples of storage devicesinclude a solid-state drive (SSD), a flash drive, a universal serial bus(USB) flash drive, and a hard disk drive (HDD). Another example of amemory sub-system is a memory module that is connected to a centralprocessing unit (CPU) via a memory bus. Examples of memory modulesinclude a dual in-line memory module (DIMM), a small outline DIMM(SO-DIMM), a non-volatile dual in-line memory module (NVDIMM), etc. Insome embodiments, the memory sub-system is a hybrid memory/storagesub-system that provides both memory functions and storage functions. Ingeneral, a host system can utilize a memory sub-system that includes oneor more memory components. The host system can provide data to be storedat the memory sub-system and can request data to be retrieved from thememory sub-system.

FIG. 1 illustrates an example computing system 100 having a memorysub-system in accordance with some embodiments of the presentdisclosure. In FIG. 1, a solid state drive 101 is shown as an example ofsuch a memory sub-system. The aggregated solid state drive 101 isconstructed using multiple component solid state drives 107 to 109. Adriver aggregator 103 of the solid state drive 101 virtualizes theentire combined capacity of the multiple component solid state drives107 to 109 as the capacity of the aggregated solid state drive 101. Thedrive aggregator 103 shields the component solid state drives 107 to 109from a host system 111 such that the host system 111 can access thememory capacity of the multiple component solid state drives 107 to 109by addressing the single solid state drive 101. Each of the componentsolid state drives 107 to 109 in FIG. 1 is another example of a memorysub-system in general.

In general, a memory sub-system can include media, such as mediaunits/memory components. The media units/memory components can bevolatile memory components, non-volatile memory components, or acombination of such. Each of the media units/memory components canperform operations to store, record, program, write, or commit new dataindependent of the operations of other media units/memory components.Thus, the media units/memory components can be used in parallel inexecuting write commands. In some embodiments, the memory sub-system isa storage system. An example of a storage system is a solid state drive(SSD). In other embodiments, the memory sub-system is a memory module.Examples of a memory module includes a DIMM, NVDIMM, and NVDIMM-P. Infurther embodiments, the memory sub-system is a hybrid memory/storagesub-system. In general, the computing system 100 can include a hostsystem 111 that uses a memory sub-system (e.g., the solid state drive101) through a computer bus 117. For example, the host system 111 canwrite data to the memory sub-system and read data from the memorysub-system.

The host system 111 can be a computing device such as a desktopcomputer, laptop computer, network server, mobile device, or suchcomputing device that includes a memory and a processing device. Thehost system 111 can include or be coupled to the memory sub-system, suchas the solid state drive 101, via a computer bus 117, so that the hostsystem 111 can read data from or write data to the memory sub-system.The host system 111 can be coupled to the memory sub-system via aphysical host interface. As used herein, “coupled to” generally refersto a connection between components, which can be an indirectcommunicative connection or direct communicative connection (e.g.,without intervening components), whether wired or wireless, includingconnections such as electrical, optical, magnetic, etc. Examples of aphysical host interface include, but are not limited to, a serialadvanced technology attachment (SATA) interface, a peripheral componentinterconnect express (PCIe) interface, universal serial bus (USB)interface, Fibre Channel, Serial Attached SCSI (SAS), a double data rate(DDR) memory bus, etc. The physical host interface can be used totransmit data between the host system 111 and the memory sub-system,such as the solid state drive 101. The host system 111 can furtherutilize an NVM Express (NVMe) interface to access the storage capacityof the memory sub-system when the memory sub-system is coupled with thehost system 111 by the PCIe interface. The physical host interface canprovide an interface for passing control, address, data, and othersignals between the host system 111 and the memory sub-system, such asthe solid state drive 101. FIG. 1 illustrates a solid state drive 101 asan example a memory sub-system. In general, the host system 111 canaccess multiple memory sub-systems via a same communication connection,multiple separate communication connections, and/or a combination ofcommunication connections.

The host system 111 includes a processing device 113 and a controller115. The processing device 113 of the host system 111 can be, forexample, a microprocessor, a central processing unit (CPU), a processingcore of a processor, an execution unit, etc. In some instances, thecontroller 115 can be referred to as a memory controller, a memorymanagement unit, and/or an initiator. In one example, the controller 115controls the communications over the computer bus 117 coupled betweenthe host system 111 and the memory sub-system, such as the solid statedrive 101.

In general, the controller 115 can send commands or requests to a memorysub-system for desired access to memory storage capacity. The controller115 can further include interface circuitry to communicate with thememory sub-system via the computer bus 117. The interface circuitry canconvert responses received from memory sub-system into information forthe host system 111.

The controller 115 of the host system 111 can communicate withcontroller 115 of the memory sub-system to perform operations such asreading data, writing data, or erasing data at the memory components ofthe memory sub-system and other such operations. In some instances, thecontroller 115 is integrated within the same integrated circuit packageof the processing device 113. In other instances, the controller 115 isseparate from the integrated circuit package of the processing device113. The controller 115 and/or the processing device 113 can includehardware such as one or more integrated circuits and/or discretecomponents, a buffer memory, a cache memory, or a combination thereof.The controller 115 and/or the processing device 113 can be amicrocontroller, special purpose logic circuitry (e.g., a fieldprogrammable gate array (FPGA), an application specific integratedcircuit (ASIC), etc.), or another suitable processor.

In general, media units/memory components of a memory sub-system (e.g.,the solid state drive 107 or 109) can include any combination of thedifferent types of non-volatile memory components and/or volatile memorycomponents. An example of non-volatile memory components includes anegative-and (NAND) type flash memory. Each of the memory components caninclude one or more arrays of memory cells such as single level cells(SLCs) or multi-level cells (MLCs) (e.g., triple level cells (TLCs) orquad-level cells (QLCs)). In some embodiments, a particular memorycomponent can include both an SLC portion and an MLC portion of memorycells. Each of the memory cells can store one or more bits of data(e.g., data blocks) used by the host system 111. Although non-volatilememory components such as NAND type flash memory are described, thememory components can be based on any other type of memory such as avolatile memory. In some embodiments, the memory components can be, butare not limited to, random access memory (RAM), read-only memory (ROM),dynamic random access memory (DRAM), synchronous dynamic random accessmemory (SDRAM), phase change memory (PCM), magneto random access memory(MRAM), Spin Transfer Torque (STT)-MRAM, ferroelectric random-accessmemory (FeTRAM), ferroelectric RAM (FeRAM), conductive bridging RAM(CBRAM), resistive random access memory (RRAM), oxide based RRAM(OxRAM), negative-or (NOR) flash memory, electrically erasableprogrammable read-only memory (EEPROM), nanowire-based non-volatilememory, memory that incorporates memristor technology, and a cross-pointarray of non-volatile memory cells. A cross-point array of non-volatilememory can perform bit storage based on a change of bulk resistance, inconjunction with a stackable cross-gridded data access array.Additionally, in contrast to many flash-based memories, cross-pointnon-volatile memory can perform a write in-place operation, where anon-volatile memory cell can be programmed without the non-volatilememory cell being previously erased. Furthermore, the memory cells ofthe memory components can be grouped as memory pages or data blocks thatcan refer to a unit of the memory component used to store data.

In general, a memory sub-system (e.g., the solid state drive 107 or 109)can have a controller that communicates with the memory components ofthe memory sub-system to perform operations such as reading data,writing data, or erasing data and other such operations (e.g., inresponse to commands scheduled on a command bus). The controller of thememory sub-system can include hardware such as one or more integratedcircuits and/or discrete components, a buffer memory, or a combinationthereof. The controller of the memory sub-system can be amicrocontroller, special purpose logic circuitry (e.g., a fieldprogrammable gate array (FPGA), an application specific integratedcircuit (ASIC), etc.), or another suitable processor. The controller ofthe memory sub-system can include a processing device (e.g., processor)configured to execute instructions stored in local memory of thecontroller. For example, the local memory of the controller of thememory sub-system can include an embedded memory configured to storeinstructions for performing various processes, operations, logic flows,and routines that control operation of the memory sub-system, includinghandling communications between the memory sub-system and a host system(e.g., 111). In some embodiments, the local memory can include memoryregisters storing memory pointers, fetched data, etc. The local memorycan also include read-only memory (ROM) for storing micro-code. While atypical memory sub-system has a controller, in another embodiment of thepresent disclosure, a memory sub-system may not include a controller,and can instead rely upon external control (e.g., provided by anexternal host, or by a processor or controller separate from the memorysub-system).

In general, the controller of a memory sub-system (e.g., the solid statedrive 107 or 109) can receive commands or operations from the hostsystem 111 and can convert the commands or operations into instructionsor appropriate commands to achieve the desired access to the memorycomponents of the memory sub-system. The controller of the memorysub-system (e.g., the solid state drive 107 or 109) can be responsiblefor other operations such as wear leveling operations, garbagecollection operations, error detection and error-correcting code (ECC)operations, encryption operations, caching operations, and addresstranslations between a logical block address and a physical blockaddress. The controller of the memory sub-system (e.g., the solid statedrive 107 or 109) can further include host interface circuitry tocommunicate with a host system (e.g., 111) via the physical hostinterface. The host interface circuitry can convert the commandsreceived from the host system into command instructions to access thememory components as well as convert responses associated with thememory components into information for the host system (e.g., 111).

A memory sub-system (e.g., the solid state drive 107 or 109) can alsoinclude additional circuitry or components. In some embodiments, thememory sub-system (e.g., the solid state drive 107 or 109) can include acache or buffer (e.g., DRAM) and address circuitry (e.g., a row decoderand a column decoder) that can receive an address from the controller ofthe memory sub-system and decode the address to access the memorycomponents in the memory sub-system.

The computing system 100 includes a drive aggregator 103 that aggregatesthe capacities of the component solid state drives 107 to 109 andvirtualize the entire combined capacity as the capacity of the singlesolid state drive 101. In some embodiments, the drive aggregator 103includes logic circuitry to translate the commands/requests from thehost system 111 into commands/requests to the solid state drives 107 to109 and/or translate the responses from the solid state drives 107 to109 into responses to the host system 111. The drive aggregator 103accesses commands from the host system 111 according to a communicationprotocol for a solid state drive to accept commands from host systems.The drive aggregator 103 constructs and transmits commands to each ofthe component solid state drives (e.g., 107 or 109) according to acommunication protocol for host systems to issue commands to solid statedrives. The drive aggregator 103 accepts responses from each of thecomponent solid state drives (e.g., 107 or 109) according to acommunication protocol between host systems and solid state drives. Thedrive aggregator 103 constructs and transmits responses to the hostsystem 111 according to communication protocol between host systems andsolid state drives. The communication protocol used between the hostsystem 111 and the driver aggregator 103 can be the same as thecommunication protocol used between the driver aggregator 103 and thecomponent solid state drives 107 to 109 in one embodiment. Thecommunication protocol used between the host system 111 and the driveraggregator 103 can be different from the communication protocol usedbetween the driver aggregator 103 and the component solid state drives107 to 109 in one embodiment. The drive aggregator 103 behaves like acontroller of a standard solid state drive to the host system 111according to one communication protocol and behaves like a standard hostsystem to the component solid state drives 107 to 109 according to thesame, or a different, communication protocol.

In the solid state drive 101, the driver aggregator 103 is connected tothe component solid state drives 107 to 109 via a bus 105. For example,the bus 105 can include point to point serial connections from thedriver aggregator 103 to the component solid state drives 107 to 109.The point to point serial connections between the driver aggregator 103and the component solid state drives 107 to 109 can be in accordancewith a serial advanced technology attachment (SATA) communicationprotocol, a peripheral component interconnect express (PCIe)communication protocol, or another protocol. The computer bus 117between the host system 111 and the drive aggregator 103 can be in inaccordance with a serial advanced technology attachment (SATA)communication protocol, a peripheral component interconnect express(PCIe) communication protocol, a universal serial bus (USB)communication protocol, a Fibre Channel communication protocol, a SerialAttached SCSI (SAS) communication protocol, a double data rate (DDR)memory bus communication protocol, etc.

The drive aggregator 103 can be implemented using an integrated circuitchip having a field programmable gate array (FPGA) or an applicationspecific integrated circuit (ASIC). Alternatively, the drive aggregator103 can be implemented at least in part via software or firmware. Forexample, the driver aggregator 103, or the processing device embeddedwithin the driver aggregator 103, can be configured to executeinstructions stored in memory for performing the operations of the driveaggregator 103 described herein. In some embodiments, the driveaggregator 103 is implemented in a single integrated circuit chipconfigured on the overall solid state drive 101 that has multiplecomponent solid state drives 107.

FIG. 2 shows a host system 111 connected to a virtualized single solidstate drive having multiple component solid state drives 107 to 109. Forexample, the virtualized single solid state drive can be used toimplement the solid state drive 101 illustrated in FIG. 1

In FIG. 2, a printed circuit board 131 is configured to have pins 133for a connection 135 to the host system 111 as a single solid statedrive 101. For example, the connection 135 can be a point to pointserial connection in accordance with SATA, PCIe, USB, or anotherstandard. Based on the communication standard, the host system 111 isconfigured to recognize the device configured on the printed circuitboard 131 as a single solid state drive 101. The host system 111addresses memory in the device based on the recognition of the device asa single solid state drive 101.

Commands from the host system 111 are received in the drive aggregator103 via the connection 135 and the pins 133. The received commands areprocessed in the drive aggregator 103 for adjustment, mapping, and/ordistribution to the component solid state drives 107 to 109. Forexample, each of the component solid state drives 107 to 109 can beimplemented as a ball grid array (BGA) solid state drive (SSD) that iscapable of processing the commands from the host system 111 directly.For example, when the connection 137 from the component solid statedrive 109 to the drive aggregator 103 is reconnected directly to thehost system 111, the host system 111 can recognize the solid state drive109 and communicate directly the solid state drive 109 to store data inthe solid state drive 109 and/or retrieve data from the solid statedrive 109.

For example, a BGA SSD 107 can have a controller 141 that is capable ofcommunicating with a host system (e.g., 111) directly to receivecommands and provide responses; and the BGA SSD 107 can have multiplemedia units (memory components) 143 to 147 that have memory cells tostore data.

The drive aggregator 103 is configured to shield the details of thecomponent solid state drives 107 to 109 from the host system 111. Thus,the host system 111 does not have to address the component solid statedrives 107 to 109 separately. For examples, according to a set ofpredetermined rules, the drive aggregator 103 can forward some commandsfrom host system 111 to one component solid state drive (e.g., 107) andforward other commands from the host system 111 to another componentsolid state drive (e.g., 109).

For example, the drive aggregator 103 can divide the logical addressspace of the entire capacity of the device configured on the printedcircuit board 131 into multiple regions. Each of the regions isassociated with a corresponding one of the component solid state drives107 to 109. When the drive aggregator 103 receives a command is receivedfrom the host system 111, the drive aggregator 103 determines the regionin which the logical address of the command is located, identifies thetarget solid state drive (e.g., 107) that is associated with thedetermined region, adjusts the command to at least map the logicaladdress in the command received in the host to the logical address inthe target solid state drive (e.g., 107), and transmits the adjustedcommand to the target solid state drive (e.g., 107).

In some embodiments, the host system 111 is configured to organize thememory capacity of the virtualized single solid state drive 101 on theprinted circuit board into named portions. A name portion of the memorycapacity is a namespace. Logical addresses can be defined withindifferent namespaces separate for the memory capacity of the virtualizedsingle solid state drive 101. For example, a first namespace allocatedon a first portion of the memory capacity of n blocks can have logicalblock addressing (LBA) addresses ranging from 0 to n−1; and a secondnamespace allocated on a second portion of the memory capacity of mblock can have LBA addresses ranging from 0 to m−1. To access a memoryblock, the host system 111 identifies the namespace and the LBA addressdefined within the namespace.

The drive aggregator 103 can be configured to distribute operationsrequested by the host system 111 to the component solid state drives 107to 109 based on namespaces. For example, the drive aggregator 103 canassign different namespaces created on the memory capacity of thevirtualized single solid state drive 101 to different component solidstate drives 107 to 109. Subsequently, the drive aggregator 103 cansimply forward the commands from the host system 111 to the componentsolid state drives based on the namespaces specified in the commands.

FIG. 3 shows a drive aggregator 103 according to one embodiment. Forexample, the drive aggregator 103 of FIG. 3 can be used on the printedcircuit board 131 of FIG. 2 and/or in the virtualized single solid statedrive 101 of FIG. 1.

The drive aggregator 103 of FIG. 3 can be integrated within a singleintegrated circuit chip. The drive aggregator 103 of FIG. 3 includes ahost interface 151 for a connection 135 to a host system (e.g., 111), atranslation logic 153, and multiple drive interfaces 155 to 157. Each ofthe drive interfaces 155 to 157 can be used for a connection (e.g., 137)to a component solid state drive (e.g., 109).

The host interface 151 is configured to implement a solid state driveside of a communication protocol between host systems and solid statedrives. Each of the drive interfaces 155 and 157 is configured toimplement a host system side of a communication protocol between hostsystems and solid state drives. In some instances, the driver interfaces155 to 157 can support different communication protocols (e.g., SATA andPCIe) such that the different types of component solid state drives 107to 109 can be used.

The translation logic 153 is configured to receive a command from thehost interface 151 and generate one or more commands for the driveinterfaces 155 to 157. When one or more corresponding responses arereceived from the drive interfaces 155 to 157, the translation logic 153generates a response to the command from the host interface 151.

The drive aggregator 103 has an address map 159 that controls theoperation of the translation logic 153. For example, the address map 159can be used to translate a logical address in the capacity of thevirtualized single solid state drive 101 to the corresponding logicaladdress in the capacity of a corresponding component solid state drive(e.g., 107 or 109) connected to one of the drive interfaces 155 to 157.Based on the address translation, the translation logic 153 can generatecorresponding commands for the respective drive interfaces (e.g., 155 or157).

In some implementations, the communication protocols used in theconnection 135 and in the connection 137 are different. Thus, thetranslation logic 153 performs the command translations according to thedifferences in the communication protocols.

In some implementations, the communication protocols used in theconnection 135 and in the connection 137 are different; and thetranslation logic 153 can simply forward a command received in theconnection 135 to the drive interface 157. For example, when a namespaceis created on the component solid state drive (e.g., 109) connected todrive interface 157, a command from the host interface 151 for read orwrite operations in the namespace can be forward to the drive interface157.

The translation logic 153 can be implemented as a field programmablegate array (FPGA), an application specific integrated circuit (ASIC), orone or more microprocessors executing a set of instructions. Theinstructions and/or the address map 159 can be stored in a local memoryunit of the drive aggregator 103. Alternatively, or in combination, theinstructions and/or the address map 159 can be stored in one or more ofthe component solid state drives (e.g., 107 to 109) connected to thedrive interfaces 155 to 157.

FIG. 4 shows a method implemented in a drive aggregator 103 according toone embodiment. For example, the method of FIG. 4 can be implemented inthe drive aggregator 103 illustrated in FIGS. 1, 2, and/or 3.

At block 201, a drive aggregator 103 receives a command from a hostsystem 111. The command specifies an operation to be performed by asolid state drive 101. The drive aggregator 103 functions as thecontroller of a single solid state drive 101 to the host system 111.Thus, the commands from the host systems 111 to the drive aggregator areconfigured as being addressed to the same solid state drive 101. Thedrive aggregator 103 is connected to multiple solid state drives 107 to109.

At block 203, the drive aggregator 103 maps an address in the commandfrom the host system 111 to an address in a solid state drive (e.g., 107or 109) among multiple solid state drives 107 to 109 that are connectedto the drive aggregator 103. The mapping can be based on a namespacespecified in the command from the host system 111, a predeterminedaddress mapping scheme, and/or an address map 159.

At block 205, the drive aggregator 103 generates and transmits a commandto the solid state drive (e.g., 107 or 109). The command to the solidstate drive (e.g., 107 or 109) is configured for the operation specifiedin the command received from the host system 111 and for the addressmapped in the solid state drive (e.g., 107 or 109).

For example, a logical address defined in a namespace created in thememory capacity of the single solid state drive 101 can be mapped to thesame logical address defined in the namespace created in the memorycapacity of a solid state drive (e.g., 107 or 109) that is assigned toimplement the namespace.

For example, the space of logical addresses defined in the entire memorycapacity of the single solid state drive 101 represented by the driveaggregator 103 can be divided into regions (e.g., according to apredefined scheme). Different regions can be mapped to the spaces oflogical addresses defined in the memory capacities of the componentsolid state drives 107 to 109.

When the communication protocol between the host system 111 and thedrive aggregator 103 is different from the communication protocolbetween the drive aggregator 103 and the component solid state drives107 to 109, the drive aggregator 103 can perform the command translationaccording to the communication protocols.

When the communication protocol between the host system 111 and thedrive aggregator 103 is same as the communication protocol between thedrive aggregator 103 and the component solid state drives 107 to 109,the drive aggregator 103 can be configured to forward the command to thetarget solid state drive 101 without changes in some implementations(e.g., when the address mapping is based on namespace).

For example, the communication protocol between the host system 111 andthe drive aggregator 103 and the communication protocol between thedrive aggregator 103 and the component solid state drives 107 to 109,the drive aggregator 103 can each be any one of standard protocols, suchas a protocol for a serial advanced technology attachment (SATA)interface, a protocol for a peripheral component interconnect express(PCIe) interface, a protocol for a universal serial bus (USB) interface,a protocol for a fibre channel, etc.

At block 207, the drive aggregator 103 receives a response from thesolid state drive (e.g., 107 or 109) that is responsive to the commandto the solid state drive (e.g., 107 or 109).

At block 209, the drive aggregator 103 generates and transmits aresponse to the host system 111 based on the response from the solidstate drive (e.g., 107 or 109), where the response to the host system isresponsive to the command from the host system for the operation and theaddress specified in the command from the host system.

In some implementations, the drive aggregator 103 performs protocoltranslation to account for the protocol differences between theconnection 135 to the host system 111 and the connection (e.g., 137) tothe component solid state drive (e.g., 109). In other implementations,the drive aggregator 103 performs further adjust for the response to thehost system 111 to account for the logical address differences betweenthe command from the host system 111 and the command to the componentsolid state drive (e.g., 109).

FIG. 5 shows a method of distributing commands received in a virtualizedsolid state drive to solid state drives. For example, the method of FIG.5 can be implemented in a virtualized solid state drive 101 of FIG. 1having component solid state drives 107 to 109 in a configurationillustrated in FIG. 2. For example, the method of FIG. 5 can beimplemented in the drive aggregator 103 illustrated in FIGS. 1, 2,and/or 3.

At block 241, a drive aggregator 103 virtualizes multiple solid statedrives 107 to 109 as a single solid state drive 101 connected to a hostsystem 111.

At block 243, the drive aggregator 103 receives a first command from thehost system 111 to create a namespace on the capacity of the virtualizedsolid state drive 101.

At block 245, the drive aggregator 103 selects a solid state drive(e.g., 107 or 109) from the multiple solid state drives 107 to 109 forthe namespace.

At block 247, the drive aggregator 103 stores data associating thenamespace with the selected solid state drive (e.g., 107 or 109).

At block 249, the drive aggregator 103 transmits the first command tothe selected solid state drive (e.g., 107 or 109) to create thenamespace in the selected solid state drive (e.g., 107 or 109).

At block 251, the drive aggregator 103 receives from the host system 111a second command identifying the namespace.

At block 253, the drive aggregator 103 transmits the second command tothe selected solid state drive (e.g., 107 or 109) based on theassociation of the namespace and the selected solid state drive.

The technique of distributing commands to component solid state drives107 to 109 as in FIG. 5 can simplify the translation logic 153 of thedrive aggregator 103 and thus reduces the complexity, energyconsumption, and cost of the translation logic 153.

In some embodiments disclosed herein, a single solid state drive isconfigured with multiple physical host interfaces that allow multiplehost systems to access the memory/storage capacity of the solid statedrive. In some implementations, a host system can use multiple paralleland/or redundant connections to the multiple physical host interfaces ofthe solid state drive for improved performance and/or reliability.

FIG. 6 shows multiple host systems 111 to 112 connected to a virtualizedsingle solid state drive 101 configured on a printed circuit board 131with multiple component solid state drives 107 to 109.

Similar to the solid state drive 101 illustrated in FIG. 2, the solidstate drive 101 illustrated in FIG. 6 can be constructed using multipleBGA SSDs (e.g., 107) as the component solid state drives 107 to 109.Each component solid state drive (e.g., 107) has a controller (e.g.,141) that is capable of servicing a host system (e.g., 111) directlywithout the drive aggregator 103, when the component solid state drive(e.g., 107) is connected directly to the host system (e.g., 111).

The drive aggregator 103 is configured to virtualize the memory/storagecapacity of the set of component solid state drives 107 to 109 as thememory/storage capacity of a single virtualized solid state drive 101and as a uniform memory/storage resource for the host systems 111 to112.

The printer circuit board 131 is configured with multiple sets of pins133 to 134. Each set of pins (e.g., 133 or 134) is sufficient toestablish a connection between a host system (e.g., 111 or 112) and thesolid state drive 101 for full access to the solid state drive 101. Forexample, a host system (e.g., 111 or 112) can transmit commands orrequests to the solid state drive 101 using any pin set (e.g., 133 or134) and receive responses to the respective commands or requests.

The multiple sets of pins 133 to 134 allow the host systems 111 to 112in FIG. 6 to communicate with the solid state drive 101 using theparallel connections 135 to 136 respectively. For example, the hostsystem 111 can send a command/request to the solid state drive 101through the connection 135 and the pins 133, while concurrently the hostsystem 112 can send a similar command/request (or a command/request of adifferent type) to the solid state drive 101 through another connection136 and the alternative pins 134. For example, the host system 111 cansend a write command at the same time as the host system 112 is sendinga write command or a read command to the solid state drive 101. Thus,the host systems 111 to 112 can share the memory/storage resourcesoffered by the solid state drive 101 as a whole.

The drive aggregator 103 of FIG. 6 can service the commands/requestsfrom each host system (e.g., 111 or 112) in a way similar to the driveaggregator 103 illustrated in and described with FIGS. 2-5.

In some instances, when two concurrent commands are mapped to a samecomponent solid state drive (e.g., 107 or 109) for execution, the driveaggregator 103 of FIG. 6 can further resolve the conflict by schedulingthe commands for non-concurrent execution, as further discussed below.

FIG. 7 shows a drive aggregator 103 having multiple host interfaces 151to 152 according to one embodiment. For example, the drive aggregator103 of FIG. 7 can be used in the solid state drive 101 of FIG. 8.

The translation logic 153 of FIG. 7 can distribute commands received ina host interface (e.g., 151 or 152) to the drive interfaces 155 to 157based on an address map 159, in a way similar to the translation logic153 of FIG. 3.

Further, when multiple commands are received concurrently in multiplehost interfaces 151 to 152, the operations of the commands may be mappedto different drive interfaces in some situations and mapped to a samedrive interface in other situations. For example, when the multiplecommands are configured to operate on logical addresses associated withthe same drive interface 155, a conflict occurs. The conflict preventsthe translation logic 153 from executing the commands concurrently usingthe drive interfaces in parallel. In such a situation, the translationlogic 153 can use a command queue 161 to schedule the sequentialexecution of the commands to avoid conflicts.

When there is no conflict, multiple commands received concurrently inmultiple host interfaces 151 to 152 can be executed in parallel byseparate component solid state drives (e.g., 107 to 109) that areconnected to the drive interfaces 155 to 157 respectively. The executioncan be performed via generating the respective commands for thecomponent solid state drives (e.g., 107 to 109) in some implementations,or via forwarding the received commands to the respective driveinterfaces 155 to 157.

When there is a conflict, the translation logic 153 can use the commandqueue 161 to schedule sequential execution of conflicting commandsreceived from different host interfaces 151 to 152. For example, whentwo commands received in the host interfaces 151 and 152 identify a samenamespace (or a logical address region) that is associated with thedrive interface 155 according to the address map 159, the translationlogic 153 can queue one of the commands in the command queue 161 andforward the other command to the drive interface 155 (or generate andtransmit a corresponding command for the operation of the other commandafter proper protocol and/or address translation). Subsequently, thetranslation logic 153 can retrieve the remaining command from thecommand queue 161 and forward it to the drive interface (or generate andtransmit a corresponding command for the operation of the commandretrieved from the command queue after proper protocol and/or addresstranslation).

In some implementations, the translation logic 153 supports executionsof commands received from a host interface (e.g., 151 or 152) out of theorder in which the commands are received from the host interface (e.g.,151 or 152). The translation logic 153 can arrange the execution ordersof commands via the command queue to increase parallel transmissions ofcommands to the drive interfaces 155 to 157 and thus improve the overallperformance of the solid state drive 101 having the drive aggregator103.

In some instances, two or more of the host interfaces 151 to 152 can beused by a same host system for increased communication bandwidth to thedrive aggregator and/or improved reliability in connection to the driveaggregator.

FIG. 8 shows a host system 111 connected to a virtualized single solidstate drive 101 via multiple parallel and/or redundant connects 135 to136. For example, the virtualized single solid state drive 101 of FIG. 8can be implemented in a way similar to the virtualized single solidstate drive 101 of FIG. 6 using a drive aggregator 103 of FIG. 7.

In FIG. 8, the virtualized single solid state drive 101 has multiplesets of pins 133 to 134 that may be connected to separate host systemsin a way as illustrated in FIG. 7. In the example of FIG. 8, themultiple sets of pins 133 to 134 of the solid state drive 101 areconnected via parallel, redundant connections to a same host system 111.Thus, the host system 111 can use any of the connections to send aspecific command to the solid state drive 101 (e.g., to write/store datain memory cells or read/retrieve data from memory cells).

For example, when one of the connections (e.g., 135 or 136) is damaged,the host system 111 can use the remaining connections (e.g., 136 or 135)to access the memory/storage capacity of the solid state drive 101.Thus, the reliability of the system is improved.

Further, the host system 111 can send multiple commands in parallel viathe connections 135 to 136 to the solid state drive 101 for execution.For example, the host system 111 can send a read command via theconnection 135 while sending a write command via the connection 136concurrently. For example, the host system 111 can use the connection135 for a read stream of data stored into a namespace that is configuredon the component solid state drive 107, while concurrently using theconnection 136 for a write stream of data retrieved from anothernamespace that is configured on another component solid state drive 109.

FIG. 9 shows a method of processing commands received in a virtualizedsolid state drive 101 via multiple host interfaces 151 to 152. Forexample, the method of FIG. 9 can be implemented in a virtualized solidstate drive 101 of FIG. 1 having component solid state drives 107 to 109in a configuration illustrated in FIG. 6 or 8. For example, the methodof FIG. 9 can be implemented in the drive aggregator 103 illustrated inFIGS. 6, 7, and/or 8. Further, the method of FIG. 9 can be used incombination with the method of FIGS. 4 and/or 5.

At block 271, a drive aggregator 103 having at least two host interfaces(e.g., 151 and 152) receives concurrently a first command in a firsthost interface (e.g., 151) and a second command in a second hostinterface (e.g., 152).

At block 273, the translation logic 153 of the drive aggregator 103determines whether the first and second commands are to be executed in asame solid state drive (e.g., 107 or 109) among multiple solid statedrives 107 to 109 that are connected to the drive aggregator 103 throughthe drive interfaces 155 to 157 of the drive aggregator 103.

At block 275, a determination that the first and second commands are tobe executed in a same solid state drive (e.g., 107 or 109) leads toblock 279; and a determination that the first and second commands are tobe executed in different solid state drives (e.g., 107 and 109) leads toblock 279.

For example, for each respective command in the first and secondcommands received in the host interfaces (e.g., 151 and 152), thetranslation logic 153 can determine the memory cells to be operatedupon. For example, the memory cells can be operated upon for readingdata or for writing data according to the logical addresses specified inrespective commands. When the memory cells are determined to be in thecomponent solid state drive (e.g., 107 or 109) connected to a driveinterface (e.g., 155 or 157), the respective command is to be executedin the component solid state drive (e.g., 107 or 109). For example, theidentification of the component solid state drive (e.g., 107 or 109) canbe made using an address map 159, based on the logical address of thememory cells specified in the respective command and/or the namespace ofthe logical address (e.g., as discussed above in connection with FIGS. 4and 5). When each command is mapped to a component solid state drive(e.g., 107 or 109), multiple concurrent commands may be mapped to a samecomponent solid state drive (e.g., 107 or 109) in some instances, andnot mapped to any same component solid state drive (e.g., 107 or 109) inother instances.

At block 277, the translation logic 153 transmits commands to two of themultiple solid state drives 107 to 109 in parallel to perform operationsof the first and second commands, since the first and second commands donot operate on the same component solid state drive (e.g., 107 or 109).

At block 279, the translation logic 153 schedules commands forsequential transmission to the same solid state drive (e.g., 107 or 109)to perform the operations of the first and second commands, because thefirst and second commands operate on the same component solid statedrive (e.g., 107 or 109). The sequential transmission resolves theconflict.

Similar to the operations in FIGS. 4 and 5, the commands transmitted tothe solid state drive(s) in parallel or in sequence to performoperations of the first and second commands can involve protocoltranslation and address translations.

For example, when the communication protocol on the host connections 135to 136 is different from the communication protocol on the driveconnections (e.g., 137), the translation logic 153 translates from theprotocol for the first and second commands to the commands to the driveinterfaces 155 to 157.

For example, when the communication protocol on the host connections 135to 136 is the same as the communication protocol on the driveconnections (e.g., 137) and the address map 159 is based on theassociation between namespaces and the component drives on which thenamespaces are hosted, the translation logic 153 can simply forward thefirst and second commands as the respective commands to the driveinterfaces 155 to 157.

For example, when the address map 159 is used to map LBA address regionsin commands received in the host interfaces 151 to 152 to different LBAaddresses in the component solid state drives 157 to 159, thetranslation logic 153 can replace the LBA addresses in the commandsreceived in the host interfaces 151 to 152 with mapped LBA addressescomputed according to the address map 159 for the respective componentsolid state drives 157 to 159.

In some embodiments disclosed herein, a virtualized single solid statedrive having multiple component solid state drives is configured to beaddressable via multiple logical address spaces. For example, themultiple logical address spaces can be used in a way similar to multiplesolid state drives each having a separate logical address space that isassociated with the host interface of the corresponding solid statedrive. However, when multiple solid state drives are used separately toprovide the separate logical address spaces, the memory/storageresources identified using a logical address space is limited to bephysically hosted within a specific solid state drive. In contrast, whenmultiple solid state drives are configured as component solid statedrives of a virtualized single solid state drive having multiple logicaladdress spaces, the memory/storage resources of each logical addressspace can be hosted among the component solid state drives for improvedperformance and/or capacity management. For example, the virtualizedsingle solid state drive can have multiple host interfaces asillustrated in FIGS. 6-8. Each of the host interfaces can be configuredto accept memory/storage access requests in a separate logical addressspace, as if the host interfaces were connected to separate solid statedrives. The drive aggregator of the virtualized single solid state drivecan use memory/storage resources in different component solid statedrives for different portions of a logical address space associated witha host interface.

FIG. 10 illustrates a virtualized single solid state drive 101configured to be accessed via separate logical address spaces 163 to 164according to one embodiment.

Similar to the virtualized single solid state drive 101 of FIG. 6 or 8,the virtualized single solid state drive 101 of FIG. 10 has multiplesets of pins 133 to 134. Each set (e.g., 133 or 134) of pins can be usedto establish a connection (e.g., 135 or 136) to a host system (e.g., 111or 112).

In FIG. 10, separate logical address spaces 163 to 164 are associatedwith the multiple sets of pins 133 to 134 respectively. For example, asame command having a same logical address can be received in thevirtualized single solid state drive 101 using separate sets of pins(e.g., 133 and 134) respectively. The identification of the logicaladdress can optionally include the use of a namespace. Since theseparate sets of pins (e.g., 133 and 134) are associated with differentlogical address spaces (e.g., 163 and 164), the same logical address inthe same commands can be considered to address different memory units inthe virtualized single solid state drive 101 of FIG. 10. The driveaggregator 103 can optionally map these different memory units to a samecomponent solid state drive (e.g., 107 or 109), or separate componentsolid state drives (e.g., 107 and 109). Each of the logical addressspaces 163 to 164 is not limited to be physically hosted in a specificone of the component solid state drives 107 to 109. Each of the logicaladdress spaces 163 to 164 can be physically hosted in more than one ofthe component solid state drives 107 to 109. Since the logical addressspaces 163 to 164 are separate from each other, the memory/resourcesaccessed via one set of pins (e.g., 133) are not accessible via anotherset of pins (e.g., 134). The drive aggregator 103 can dynamicallydistribute the memory/storage resources of the logical address spaces163 to 164 based on the workloads and/or usage patterns of the logicaladdress spaces 163 to 164.

In some implementations, some or all of the different sets of pins 133to 134 can be configured to be associated with a same logical addressspace. For example, when the sets of pins 133 to 134 are connected to asame host system 111 via parallel connections 135 to 136, in a wayillustrated in FIG. 8, the sets of pins 133 to 134 can be configured toshare a same logical address space. Thus, the host system 111 can accessdata stored in a memory unit in one of the component solid state drives107 to 109 using any of the connections 135 to 136 to the pins 133 to134. Optionally, the host system 111 can configure some of the sets ofpins 133 to 134 to share a same logical address space, but not otherset(s) of pins.

Similarly, when the sets of pins 133 to 134 are connected to separatehosts 111 to 112, in a way illustrated in FIG. 6, some or all of thedifferent sets of pins 133 to 134 can be configured to be associatedwith a same logical address space. Thus, some or all of the host systems111 to 112 can share the same logical address space and a set of memoryunits associated with the logical address space.

For example, during an initialization process, the host system(s) (e.g.,111 to 112) can send commands to the sets of pins 133 to 134 to indicatethe sharing status of the logical address spaces associated with thesets of pins 133 to 134. The drive aggregator 103 is configured toimplement the sharing via mapping addresses of shared logical addressspaces to the same set of memory resources in the component solid statedrives 107 to 109 and mapping addresses of non-shared logical addressspaces to the separate sets of memory resources in the component solidstate drives 107 to 109.

Further, in some implementations, the host system(s) (e.g., 111 to 112)can send commands to request partial sharing of the logical addressspaces 163 to 164. For example, a logical address region (e.g.,represented by a namespace) in the logical address space 163 can beconfigured as being shared with the corresponding logical address region(e.g., represented by a corresponding namespace) in the logical addressspace 164. Thus, any of the separate connections 135 and 136 can be usedto access the same data stored in the same set of memory units allocatedto the share logical address region between the logical address spaces163 and 164. For example, data stored via the connection 135 in theshared logical address region can be accessed via the alternativeconnection 136.

However, some logical address regions can be not shared between logicaladdress spaces 163 and 164. Thus, the data stored in the non-sharedlogical address regions can be limited to be accessed via the respectiveconnections 135 and 136 for the respective logical address spaces 163and 164. For example, data stored via the connection 135 in a non-sharedlogical address region is prohibited to be access via the connection136.

FIG. 11 illustrates a drive aggregator 103 configured to facilitateaccess to memory/storage resources in a virtualized single solid statedrive using separate logical address spaces. For example, the driveaggregator 103 of FIG. 11 can be used in the solid state drive 101 ofFIG. 10.

Like the drive aggregator 103 of FIG. 7, the drive aggregator 103 ofFIG. 103 of FIG. 11 has multiple host interfaces 151 to 152 for separateconnections 135 to 136 to one or more host systems (e.g., 111 to 112).

In general, the host interfaces 151 to 152 of the drive aggregator 103of FIG. 103 of FIG. 11 are associated with separate logical addressspaces 163 to 164 respectively. The address maps 158 to 159 areconfigured for the logical address spaces 163 to 164 respectively.

When the logical address spaces 163 to 164 have no shared regions, theaddress maps 158 to 159 have no overlapping portions. For example, theaddress map 158 maps the logical addresses in the space 163 to a set ofmemory units connected to the drive interfaces 155 to 157; the addressmap 158 maps the logical addresses in the space 164 to another set ofmemory units connected to the drive interfaces 155 to 157; and differentsets of memory units identified in the address maps 158 and 159 have nocommon memory units.

When some of the logical address spaces 163 to 164 are partially shared(e.g., in response to configuration commands received from the hostsystem(s)), the address maps 158 to 159 have overlapping portions. Forexample, the address map 158 maps a portion of logical addresses in thespace 163 to a set of memory units connected to the drive interfaces 155to 157; the address map 158 maps a portion of the logical addresses inthe space 164 to another set of memory units connected to the driveinterfaces 155 to 157. When the portion of the logical addresses in thespace 163 and the portion of the logical addresses in the space 164 areconfigured to be shared across the logical address spaces 163 and 164,the address map 158 maps the portion of logical addresses in the space163 to the same set of memory units that is mapped to by the address map159 for the portion of the logical addresses in the space 164. However,when the portion of the logical addresses in the space 163 and theportion of the logical addresses in the space 164 are configured to benot shared across the logical address spaces 163 and 164, the set ofmemory units to which the portion of logical addresses in the space 163is mapped by the address map 158 do not share any memory unit in the setof memory units to which the portion of the logical addresses in thespace 164 is mapped by the address map 159.

Similarly, the drive aggregator 103 can configured the address maps 158to 159 to allow some or all of the host interfaces 151 to 152 to share asame logical address space. The sharing can be implemented by theaddress maps 158 to 159 of the corresponding host interfaces by mappingto the same set of memory units connected to the drive interfaces 155 to157. In some instances, the sharing can be implemented via sharing anaddress map for some or all of the host interfaces 151 to 152.

FIGS. 12-14 illustrate examples of address maps. For example, theaddress maps 154 illustrated in FIGS. 12-14 can be used in the driveaggregator 103 of FIG. 11.

In FIG. 12, namespaces 181 and 182 created via commands received viaseparate host interfaces 151 and 152 are considered as differentnamespaces. When the namespaces 181 and 182 have the same identificationin the commands received via the separate host interfaces 151 and 152,the namespaces 181 and 182 of the host interfaces 151 and 152 are mappedto different drive interfaces 155 and 157. Thus, commands addressingusing the same namespace identification but different host interfacesare hosted in different component solid state drives (e.g., 107 and109); and the data stored using the namespace identification in commandstransmitted via one host interface (e.g., 151) cannot be accessed viacommands transmitted via another host interface (e.g., 152).

Optionally, the same identification of namespaces 181 and 183 of thehost interfaces 151 and 152 can be mapped to different namespaceidentifications using the address map 154. The different namespaceidentifications can be used to create corresponding namespaces in a samecomponent solid state drive (e.g., 107) connected to a same driveinterface (e.g., 155) or in different component solid state drive (e.g.,107 and 109) connected to different drive interface (e.g., 155 and 157).

FIG. 13 illustrates a configuration where a namespace 181 is sharedbetween two host interfaces 151 and 152. The namespace 181 mapped to adrive interface 155. Based on the address map 154 of FIG. 13, commandsidentifying the namespace and received either in the host interface 151or in the host interface 152 can be forward to the drive interface 155to access the same set of memory units. For example, a host connection135 can be used to store data into the namespace 181 hosted in thecomponent solid state drive (e.g., 107) connected to the drive interface155; and another host connection 136 can be used to retrieve the datafrom the namespace 181 hosted in the same component solid state drive(e.g., 107) connected to the same drive interface 155.

In general, multiple namespaces can be mapped to a drive interface 155.Some of the namespaces mapped to the drive interface 155 can be sharedacross multiple host interfaces (e.g., 151 and 152), while othernamespaces mapped to the drive interface 155 can be not shared amonghost interfaces.

FIG. 14 illustrates a configuration where the namespaces 181 and 183created via a host interface 151 are hosted on different component solidstate drives (e.g., 107 and 109) connected to different drive interfaces155 and 157.

In general, some of the namespaces 181 and 183 created via the hostinterface 151 may be shared across multiple host interfaces; and some ofthe namespaces 181 and 183 created via the host interface 151 may be notshared with any other host interfaces. Thus, various combinations ofFIGS. 12-14 and alternatives can be implemented.

FIG. 15 shows a method of accessing memory/storage resources in avirtualized single solid state drive using separate logical addressspaces. For example, the method of FIG. 15 can be implemented in avirtualized solid state drive 101 of FIG. 1 having component solid statedrives 107 to 109 in a configuration illustrated in FIG. 2, 6, 8, or 10.For example, the method of FIG. 15 can be implemented in the driveaggregator 103 illustrated in FIGS. 6-8, 10, and/or 11 with address mapsillustrated in FIGS. 11, 12, 13, and/or 14. Further, the method of FIG.15 can be used in combination with the method of FIGS. 4, 5, and/or 9.

At block 281, a drive aggregator 103 is configured to associate itsmultiple host interfaces 151 to 152 with different logical addressspaces 163 to 164.

At block 283, the drive aggregator 103 maps the different logicaladdress spaces 163 to 164 to an aggregated capacity of a plurality ofcomponent solid state drives 107 to 109 that are connected to the driveaggregator 103 in a virtualized signal solid state drive 101.

At block 285, the drive aggregator 103 receives concurrently via themultiple host interfaces 151 to 152 first commands from parallelconnections 135 to 136 to one or more host systems (e.g., 111 and/or112).

At block 287, the drive aggregator 103 interprets the first commandsreceived from the host interfaces 151 to 152 in the different logicaladdress spaces 163 to 164.

For example, the drive aggregator 103 can be configured with separateaddress maps 158 to 159 associated with the multiple host interfaces 151to 152 respectively to translate from logical addresses identified inthe commands received from the host interfaces 151 to 152 to logicaladdresses in commands transmitted from the drive aggregator 103 to theplurality of component solid state drives 107 to 109.

At block 289, the drive aggregator 103 transmits, to the plurality ofcomponent solid state drives 107 to 109, second commands based oninterpreting the first commands in the different logical address spaces163 to 164.

For example, the multiple host interfaces 151 to 152 can include a firsthost interface 151 and a second host interface 152, where the first hostinterface 151 and the second host interface 152 are associated with asame logical address space that is separate and different from at leastone other logical address space associated with a third interface in themultiple host interfaces 151 to 152. Thus, data stored via commandstransmitted via the first is not addressable via commands transmittedvia the third interface but addressable via commands transmitted via thesecond interface.

For example, the multiple host interfaces 151 to 152 can include a firsthost interface 151 associated with a first logical address space and asecond host interface 152 associated with a second logical addressspace; an address map 158 maps the first logical address space to afirst portion of the aggregated capacity of the plurality of componentsolid state drives 107 to 109; and an address map 159 maps the secondlogical address space to a second portion of the aggregated capacity ofthe plurality of component solid state drives 107 to 109. The firstportion of the aggregated capacity and the second portion of theaggregated capacity partially can be completely separate from eachother, or be configured to partially overlap with each other.

When the first portion of the aggregated capacity and the second portionof the aggregated capacity partially are configured to partially overlapwith each other, a first portion of data stored via commands transmittedvia the first host interface 151 is not addressable via commandstransmitted via the second host interface 152; and a second portion ofdata stored via commands transmitted via the first host interface 151 isaddressable via commands transmitted via the second host interface 152.

For example, a namespace 181 associated with the first host interface151 and a namespace 183 associated with the second host interface 152can be mapped to separate, non-overlapping portions of the aggregatedcapacity of the component solid state drives 107 to 109, or mapped to anoverlapping part of the first portion of the aggregated capacity and thesecond portion of the aggregated capacity.

The methods discussed above (e.g., in connection with FIGS. 4, 5, 9and/or 15) can be performed by processing logic that can includehardware (e.g., processing device, circuitry, dedicated logic,programmable logic, microcode, hardware of a device, integrated circuit,etc.), software (e.g., instructions run or executed on a processingdevice), or a combination thereof. In some embodiments, the methods ofFIGS. 4, 5, 9 and/or 15 are performed at least in part by the driveaggregator 103 of FIG. 1, 2, 3, 6, 7, 8, 10, or 11. Although shown in aparticular sequence or order, unless otherwise specified, the order ofthe operations can be modified. Thus, the illustrated embodiments shouldbe understood only as examples, and the illustrated operations can beperformed in a different order, and some operations can be performed inparallel. Additionally, one or more operations can be omitted in variousembodiments. Thus, not all operations are required in every embodiment.Other operation flows are possible.

In some implementations, a communication channel between the host system111 and a memory sub-system (e.g., the solid state drive 101) includes acomputer network, such as a local area network, a wireless local areanetwork, a wireless personal area network, a cellular communicationsnetwork, a broadband high-speed always-connected wireless communicationconnection (e.g., a current or future generation of mobile networklink); and the host system 111 and the memory sub-system can beconfigured to communicate with each other using data storage managementand usage commands similar to those in NVMe protocol.

Some embodiments involving the operations of the drive aggregator 103can be implemented using computer instructions executed by one or moremicroprocessors. The computer instructions can be configured as thefirmware of the solid state drive 101. In some instances, hardwarecircuits can be used to implement at least some of the functions. Thefirmware can be initially stored in the non-volatile storage media, oranother non-volatile device, and loaded into the volatile DRAM and/orthe in-processor cache memory for execution by the microprocessors ofthe drive aggregator.

A non-transitory computer storage medium can be used to storeinstructions of the firmware of a memory sub-system (e.g., the solidstate drive 101, or any of the component solid state drives 107 to 109).When the instructions are executed by the microprocessors, theinstructions cause the memory sub-system to perform a method discussedabove.

In general, an example machine of a computer system can have a set ofinstructions, for causing the machine to perform any one or more of themethods discussed herein. In some embodiments, such a computer systemcan correspond to a host system (e.g., the host system 111 of FIG. 1)that includes, is coupled to, or utilizes a memory sub-system (e.g., thesolid state drive 101 of FIG. 1) or can be used to perform theoperations of a drive aggregator 103 (e.g., to execute instructions toperform operations corresponding to the drive aggregator 103 describedwith reference to FIGS. 1-15). In alternative embodiments, the machinecan be connected (e.g., networked) to other machines in a LAN, anintranet, an extranet, and/or the Internet. The machine can operate inthe capacity of a server or a client machine in client-server networkenvironment, as a peer machine in a peer-to-peer (or distributed)network environment, or as a server or a client machine in a cloudcomputing infrastructure or environment.

The machine can be a personal computer (PC), a tablet PC, a set-top box(STB), a Personal Digital Assistant (PDA), a cellular telephone, a webappliance, a server, a network router, a switch or bridge, or anymachine capable of executing a set of instructions (sequential orotherwise) that specify actions to be taken by that machine. Further,while a single machine is illustrated, the term “machine” shall also betaken to include any collection of machines that individually or jointlyexecute a set (or multiple sets) of instructions to perform any one ormore of the methodologies discussed herein.

The example machine can include a processing device, a main memory(e.g., read-only memory (ROM), flash memory, dynamic random accessmemory (DRAM) such as synchronous DRAM (SDRAM) or Rambus DRAM (RDRAM),static random access memory (SRAM), etc.), and a data storage system,which communicate with each other via a bus (which can include multiplebuses).

A processing device discussed herein can include one or moregeneral-purpose processing devices such as a microprocessor, a centralprocessing unit, or the like. More particularly, the processing devicecan be a complex instruction set computing (CISC) microprocessor,reduced instruction set computing (RISC) microprocessor, very longinstruction word (VLIW) microprocessor, or a processor implementingother instruction sets, or processors implementing a combination ofinstruction sets. A processing device discussed herein can also be oneor more special-purpose processing devices such as an applicationspecific integrated circuit (ASIC), a field programmable gate array(FPGA), a digital signal processor (DSP), network processor, or thelike. A processing device generally is configured to executeinstructions for performing the operations and steps discussed herein.The example machine can further include a network interface device tocommunicate over a computer network.

The data storage system disclosed herein can include a machine-readablestorage medium (also known as a computer-readable medium) on which isstored one or more sets of instructions or software embodying any one ormore of the methodologies or functions described herein. Theinstructions can also reside, completely or at least partially, withinthe main memory and/or within the processing device during executionthereof by the computer system, the main memory and the processingdevice also constituting machine-readable storage media. Themachine-readable storage medium, data storage system, and/or main memorycan correspond to the memory sub-system.

In one embodiment, the instructions stored in the example machineinclude instructions to implement functionality corresponding to a driveaggregator 103 (e.g., as described with reference to FIGS. 1-15). Whilethe machine-readable storage medium may be discussed in an embodiment tobe a single medium, the term “machine-readable storage medium” should betaken to include a single medium or multiple media that store the one ormore sets of instructions. The term “machine-readable storage medium”shall also be taken to include any medium that is capable of storing orencoding a set of instructions for execution by the machine and thatcause the machine to perform any one or more of the methodologies of thepresent disclosure. The term “machine-readable storage medium” shallaccordingly be taken to include, but not be limited to, solid-statememories, optical media, and magnetic media.

Some portions of the preceding detailed descriptions have been presentedin terms of algorithms and symbolic representations of operations ondata bits within a computer memory. These algorithmic descriptions andrepresentations are the ways used by those skilled in the dataprocessing arts to most effectively convey the substance of their workto others skilled in the art. An algorithm is here, and generally,conceived to be a self-consistent sequence of operations leading to adesired result. The operations are those requiring physicalmanipulations of physical quantities. Usually, though not necessarily,these quantities take the form of electrical or magnetic signals capableof being stored, combined, compared, and otherwise manipulated. It hasproven convenient at times, principally for reasons of common usage, torefer to these signals as bits, values, elements, symbols, characters,terms, numbers, or the like.

It should be borne in mind, however, that all of these and similar termsare to be associated with the appropriate physical quantities and aremerely convenient labels applied to these quantities. The presentdisclosure can refer to the action and processes of a computer system,or similar electronic computing device, that manipulates and transformsdata represented as physical (electronic) quantities within the computersystem's registers and memories into other data similarly represented asphysical quantities within the computer system memories or registers orother such information storage systems.

The present disclosure also relates to an apparatus for performing theoperations herein. This apparatus can be specially constructed for theintended purposes, or it can include a general purpose computerselectively activated or reconfigured by a computer program stored inthe computer. Such a computer program can be stored in a computerreadable storage medium, such as, but not limited to, any type of diskincluding floppy disks, optical disks, CD-ROMs, and magnetic-opticaldisks, read-only memories (ROMs), random access memories (RAMs), EPROMs,EEPROMs, magnetic or optical cards, or any type of media suitable forstoring electronic instructions, each coupled to a computer system bus.

The algorithms and displays presented herein are not inherently relatedto any particular computer or other apparatus. Various general purposesystems can be used with programs in accordance with the teachingsherein, or it can prove convenient to construct a more specializedapparatus to perform the method. The structure for a variety of thesesystems will appear as set forth in the description below. In addition,the present disclosure is not described with reference to any particularprogramming language. It will be appreciated that a variety ofprogramming languages can be used to implement the teachings of thedisclosure as described herein.

The present disclosure can be provided as a computer program product, orsoftware, that can include a machine-readable medium having storedthereon instructions, which can be used to program a computer system (orother electronic devices) to perform a process according to the presentdisclosure. A machine-readable medium includes any mechanism for storinginformation in a form readable by a machine (e.g., a computer). In someembodiments, a machine-readable (e.g., computer-readable) mediumincludes a machine (e.g., a computer) readable storage medium such as aread only memory (“ROM”), random access memory (“RAM”), magnetic diskstorage media, optical storage media, flash memory components, etc.

In this description, various functions and operations are described asbeing performed by or caused by computer instructions to simplifydescription. However, those skilled in the art will recognize what ismeant by such expressions is that the functions result from execution ofthe computer instructions by one or more controllers or processors, suchas a microprocessor. Alternatively, or in combination, the functions andoperations can be implemented using special purpose circuitry, with orwithout software instructions, such as using Application-SpecificIntegrated Circuit (ASIC) or Field-Programmable Gate Array (FPGA).Embodiments can be implemented using hardwired circuitry withoutsoftware instructions, or in combination with software instructions.Thus, the techniques are limited neither to any specific combination ofhardware circuitry and software, nor to any particular source for theinstructions executed by the data processing system.

In the foregoing specification, embodiments of the disclosure have beendescribed with reference to specific example embodiments thereof. Itwill be evident that various modifications can be made thereto withoutdeparting from the broader spirit and scope of embodiments of thedisclosure as set forth in the following claims. The specification anddrawings are, accordingly, to be regarded in an illustrative senserather than a restrictive sense.

What is claimed is:
 1. A solid state drive, comprising: a driveaggregator having multiple host interfaces; and a plurality of componentsolid state drives connected to the drive aggregator, each of thecomponent solid state drives having a controller capable of processingcommands from host systems; wherein the drive aggregator is configuredto associate the host interfaces with different logical address spaces,interpret commands received from the host interfaces in the differentlogical address spaces, and implement the commands using the pluralityof component solid state drives.
 2. The solid state drive of claim 1,wherein the drive aggregator is configured with separate address mapsassociated with the multiple host interfaces respectively to translatefrom logical addresses identified in the commands received from the hostinterfaces to logical addresses in commands transmitted from the driveaggregator to the plurality of component solid state drives.
 3. Thesolid state drive of claim 2, wherein data stored via commandstransmitted via a first interface among the multiple host interfaces isnot addressable via commands transmitted via a second interface amongthe multiple host interfaces.
 4. The solid state drive of claim 2,wherein data stored via commands transmitted via a first interface amongthe multiple host interfaces is not addressable via commands transmittedvia a second interface among the multiple host interfaces but isaddressable via commands transmitted via a third interface among themultiple host interfaces.
 5. The solid state drive of claim 2, wherein afirst portion of data stored via commands transmitted via a firstinterface among the multiple host interfaces is not addressable viacommands transmitted via a second interface among the multiple hostinterfaces; and a second portion of data stored via commands transmittedvia the first interface is addressable via commands transmitted via thesecond interface.
 6. The solid state drive of claim 2, furthercomprising: a printed circuit board having multiple sets of pins, eachset of pins is configured for a connection to a host system over acomputer bus; wherein the drive aggregator and the plurality ofcomponent solid state drives are mounted on the printed circuit board.7. The solid state drive of claim 6, wherein each of the component solidstate drives is integrated within an integrated circuit package having aball grid array (BGA) form factor.
 8. The solid state drive of claim 7,wherein the drive aggregator further comprises: a plurality of driveinterfaces configured to communicate with the plurality of componentsolid state drives respectively; and a translation logic coupled betweenthe host interfaces and the plurality of drive interfaces to generatecommands to the component solid state drives based on the address maps.9. The solid state drive of claim 8, wherein the host interfaces areconfigured according to a first protocol of communications between hostsystems and solid state drives; the plurality of drive interfaces areconfigured in accordance with a second protocol of communicationsbetween host systems and solid state drives; and each of the firstprotocol and the second protocol is one of: a protocol for a serialadvanced technology attachment (SATA) interface; a protocol for aperipheral component interconnect express (PCIe) interface; a protocolfor a universal serial bus (USB) interface; and a protocol for a fibrechannel.
 10. A method, comprising: associating, by a drive aggregatorhaving multiple host interfaces, the host interfaces with differentlogical address spaces; mapping, by the drive aggregator, the differentlogical address spaces to an aggregated capacity of a plurality ofcomponent solid state drives connected to the drive aggregator;receiving, concurrently in the drive aggregator via the multiple hostinterfaces, first commands from parallel connections to one or more hostsystems; interpreting, by the drive aggregator, the first commandsreceived from the host interfaces in the different logical addressspaces; and transmitting, from the drive aggregator to the plurality ofcomponent solid state drives, second commands based on interpreting thefirst commands in the different logical address spaces.
 11. The methodof claim 10, wherein the multiple host interfaces include a first hostinterface and a second host interface; and the first host interface andthe second host interface are associated with a same logical addressspace.
 12. The method of claim 11, wherein the multiple host interfacesfurther include a third host interface; and the first host interface andthe second host interface are associated with the same logical addressspace that is different from a logical address space associated with thethird host interface.
 13. The method of claim 10, wherein the multiplehost interfaces include a first host interface associated with a firstlogical address space and a second host interface associated with asecond logical address space; the first logical address space is mappedto a first portion of the aggregated capacity of the plurality ofcomponent solid state drives; and the second logical address space ismapped to a second portion of the aggregated capacity of the pluralityof component solid state drives.
 14. The method of claim 13, wherein thefirst portion of the aggregated capacity and the second portion of theaggregated capacity partially overlap with each other.
 15. The method ofclaim 14, wherein a namespace associated with the first host interfaceand a namespace associated with the second host interface are mapped toan overlapping part of the first portion of the aggregated capacity andthe second portion of the aggregated capacity.
 16. A driver aggregator,comprising: multiple host interfaces, each configured to communicatewith a host system; a plurality of drive interfaces to communicate witha plurality of component solid state drives respectively; and atranslation logic coupled between host interfaces and the plurality ofdrive interfaces, wherein the translation logic is configured tointerpret addresses in commands received in the multiple host interfacesin different logical address spaces.
 17. The driver aggregator of claim16, further comprising: an integrated circuit package, wherein themultiple host interfaces, the translation logic and the plurality ofdrive interfaces are packaged in the integrated circuit package; whereinthe translation logic includes a field programmable gate array (FPGA) oran application specific integrated circuit (ASIC).
 18. The driveraggregator of claim 17, wherein each of the host interfaces isconfigured to implement a point to point serial connection between ahost system and a solid state drive; and each of the plurality of driveinterfaces is configured to implement a point to point serial connectionbetween a host system and a solid state drive.
 19. The driver aggregatorof claim 18, wherein a subset of the multiple host interfaces areconfigured to share a common logical address space in interpretation ofaddresses received in the subset of multiple host interfaces.
 20. Thedriver aggregator of claim 18, wherein a subset of the different logicaladdress spaces has an overlapping region that is mapped to a same set ofmemory units in the plurality of component solid state drives; and thememory units are addressable using commands transmitted to hostinterfaces associated with the subset of the different logical addressspaces.